Source : Webster's Revised Unabridged Dictionary (1913)

Angle of entry \An"gle of en"try\ (A["e]ronautics)
   The angle between the tangent to the advancing edge (of an
   a["e]rocurve) and the line of motion; -- contrasted with
   {angle of trail}, which is the angle between the tangent to
   the following edge and the line of motion.